In mathematics, an average, or central tendency of a data set refers to a measure of the "middle" or "expected" value of the data set. There are many different descriptive statistics that can be chosen as a measurement of the central tendency of the data items. The most common method is the arithmetic mean, but there are many other types of averages. (An axiomatic approach to averages is provided by John Bibby (1974) “Axiomatisations of the average and a further generalization of monotonic sequences,” Glasgow Mathematical Journal, vol. 15, pp. 63–65.)

Central tendency is an average of a set of measurements, the word average being variously construed as mean, median, or other measure of location, depending on the context. Central tendency is a descriptive statistic analogous to center of mass in physical terms. The term is used in some fields of empirical research to refer to what statisticians sometimes call "location". A "measure of central tendency" is either a location parameter or a statistic used to estimate a location parameter.

There are several different kinds of calculations for central tendency, the kind of calculation depending on the type of data (level of measurement) for which the central tendency is being calculated.